Biped toy that can walk on two feet

ABSTRACT

By attaining a certain correlation between shifting the weight of a toy main body and shifting the center of gravity the toy main body between legs thereof there is provided a biped toy that can walk on two feet as naturally as a human being walks without falling down. Left and right legs can be forwarded as naturally as the human being does by positioning the center of gravity above one of the legs which supports the toy main body. With a view to eliminating unstable actions of leg portions, fulcrums thereof are positioned rearward, with a view to eliminating unstable actions of a torso, a fulcrum thereof is positioned rearward, and with a view to eliminating unstable actions of the toy main body, fulcrums of the left and right foot portions are each positioned either inwardly or outwardly.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a biped toy that can walk on two feet as naturally as a human being walks by lifting up left and right legs thereof alternately while shifting the weight of the toy main body.

[0003] 2. Description of the Related Art

[0004] When walking a conventional biped toy scuffs with left and right feet thereof being in contact with the ground or the like and therefore the toy cannot walk as smoothly as a robot walks.

[0005] In order to allow a biped toy to walk as naturally as a human being does there is a certain correlation to be attained between shifting the weight of a toy main body and shifting the center of gravity thereof between the legs thereof.

[0006] With the prior art, however, since the aforesaid technique of shifting the weight and center of gravity has not been materialized, if the natural walk is tried to be realized by lifting up the left and right legs of a biped toy alternately, the toy falls down, and therefore when walking the toy has to scuff with the left and right feet thereof being in contact with the ground or the like.

[0007] The present invention has been made in view of the problem inherent in the prior art and an object thereof is to provide a biped toy that can walk as naturally as a human being does while lifting up alternately left and right legs thereof by solving the correlation between shifting the weight of the toy main body and shifting the center of gravity thereof between the legs.

SUMMARY OF THE INVENTION

[0008] With a view to attaining the object, according to a first aspect of the present invention, there is provided a biped toy that can walk on two feet by virtue of the driving force of a motor, wherein legs are rotatably supported on a torso, wherein the motor having disc cams mounted on an output shaft thereof and levers for transmitting the rotations of the cams are disposed in the interior of the torso, wherein the legs are each constituted by a leg portion and a foot portion, the leg portion and the foot portion being each rotatably supported, and wherein a link mechanism is disposed in each of the legs to which the driving force is transmitted by the levers, whereby with the right leg of the legs being stepped forward by a step a toy main body is inclined leftward so that the center of gravity thereof is positioned directly above the left leg of the legs, then, in order to allow the left leg to alternately be stepped forward by a step the center of gravity is shifted to the right leg ,and after the center of gravity has been so shifted the left leg is lifted up while the torso is being shifted rearward so that the weight thereof is so shifted for advancement.

[0009] According to the first aspect of the present invention, the toy main body is prevented from falling down from the lost of its balance by shifting the weight of the toy main body and shifting the center of gravity thereof between the legs, whereby the toy main body can walk as naturally as a human being walks. Namely, in shifting the weight of the toy main body, with the right leg being stepped forward by a step, the toy main body is inclined leftward so that the center of gravity is positioned directly above the left leg.

[0010] Then, the center of gravity is shifted from the left leg to the right leg in a diagonal fashion, and after the center of gravity has been so shifted the toy main body lifts up the left leg to advance while shifting the weight thereof rearward.

[0011] In order to allow the left leg to be stepped forward by a step from that condition, the toy main body is inclined rightward so that the weight thereof is so shifted, when the center of gravity is positioned directly above the right leg.

[0012] Thereafter, the center of gravity is diagonally shifted from the right leg to the left leg, and after the center of gravity has been so shifted, the toy main body lifts up the right leg to advance while shifting the weight thereof rearward. Thus, the toy main body can walk as naturally as a human being walks while lifting up the left and right legs alternately with the torso being shifted by shifting the weight of the toy main body and shifting the center of gravity thereof between the legs.

[0013] According to a second aspect of the present invention, there is provided a biped toy that can walk on two feet as set forth in the first aspect of the invention, wherein the biped toy can walk while lifting up the left and right legs alternately by positioning the center of gravity above either the left leg or the right leg which bears the weight of the toy main body.

[0014] According to the second aspect of the present invention, the legs can be moved by alternately shifting the center of gravity above the supporting leg of the two legs.

[0015] Namely, with the right leg being stepped forward by a step, the center of gravity is positioned on the left leg which is being the supporting leg.

[0016] Then, in order to allow the left leg to be stepped forward by a step, the center of gravity is shifted to the right leg, and after the center of gravity has been so shifted, the left leg is lifted up to advance a step while the torso is being shifted rearward.

[0017] With the left leg being stepped forward by a step, the center of gravity is being positioned on the right leg which is being the supporting leg. The center of gravity is shifted to the left leg in order to allow the right leg to be stepped forward by a step, and after the center of gravity has been so shifted, the right leg is then lifted up so to advance another step while the torso is being shifted rearward.

[0018] By repeating the series of actions the toy can walk as naturally as a human being walks while lifting up the left and right legs alternately

[0019] According to a third aspect of the present invention, there is provided a biped toy that can walk on two feet as set forth in the first or second aspect of the invention, wherein joint portions of the leg portions can be flexed in a certain direction by positioning fulcrums of the leg portions rearward.

[0020] According to the third aspect of the present invention, the fulcrums of the leg portions are positioned rearward in order to eliminate unstable actions of the leg portions.

[0021] According to the construction, the joint portion between the torso and the upper leg, the joint portion between the upper leg and the lower leg and the join portion between the lower leg and the foot can be flexed in the certain direction, whereby natural walking actions can be performed.

[0022] According to a fourth aspect of the present invention, there is provided a biped toy that can walk on two feet as set forth in any of the first to third aspect of the invention, wherein the torso can be inclined forward by positioning a fulcrum of the torso rearward.

[0023] According to the fourth aspect of the present invention, the fulcrum of the torso is positioned rearward.

[0024] According to the construction, the torso can be inclined forward, whereby natural walking actions can be performed.

[0025] According to a fifth aspect of the present invention, there is provided a biped toy that can walk on two feet as set forth in any of the first to fourth aspects of the invention, wherein the balance of the toy main body can be maintained by positioning a fulcrum of the foot portion inwardly or outwardly.

[0026] According to the fifth aspect of the invention, the fulcrums of the foot portions are positioned either inwardly or outwardly in order to eliminate unstable actions of the foot portions.

[0027] According to the construction, being made to keep the balance, the toy main body are allowed to walk naturally.

[0028] Thus, according to the present invention, the toy main body can perform natural walking actions without falling down by shifting the weight of the toy main body, as well as shifting the center of gravity thereof between the legs. In addition, in moving forward the left and right legs, natural leg actions can be attained by positioning the center of gravity above the supporting leg.

[0029] Additionally, the fulcrums of the leg portions are positioned rearward in order to eliminate unstable actions of the leg portions. In addition, the fulcrum of the torso is positioned rearward in order to eliminate unstable actions of the torso. Furthermore, the fulcrums of the left and right foot portions are positioned either inwardly or outwardly in order to eliminate unstable actions of the toy main body.

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Further objects and advantages of the present invention will be apparent from the following description with reference to the accompanying drawings, wherein:

[0031]FIG. 1 is a perspective view showing the external appearance of an embodiment of the present invention;

[0032]FIG. 2 is a side view of a toy main body, as viewed from the right side, showing a mounting structure of a left leg;

[0033]FIG. 3 is a front view of the toy main body showing the mounting structure of the left leg;

[0034]FIG. 4 is a diagram showing a transmission mechanism of the driving force of a motor according to the present invention;

[0035]FIG. 5 is an enlarged view of FIG. 4;

[0036]FIG. 6 is a diagram showing the transmission mechanism of the driving force of the motor according to the present invention;

[0037]FIG. 7 is an enlarged perspective view showing a mounting structure of a foot portion;

[0038]FIG. 8 is a diagram showing a state in which an upper leg is swung left and right;

[0039]FIG. 9 is a diagram showing a state in which a lower leg is swung left and right;

[0040]FIG. 10 is a diagram showing a state in which the foot portion is tilted back and forth;

[0041]FIG. 11 is a diagram showing a state in which the foot portion is tilted left and right;

[0042]FIG. 12 is an explanatory view of a state in which the foot portion is tilted left and right;

[0043]FIG. 13 is an explanatory view of a state in which the foot portion is tilted left and right;

[0044]FIG. 14 is an explanatory view of a state in which the foot portion is tilted left and right;

[0045]FIG. 15 is a diagram showing a walking mechanism according to the present invention ;

[0046]FIG. 16 is a diagram showing the waking mechanism according to the present invention;

[0047]FIG. 17 is a diagram showing the waking mechanism according to the present invention;

[0048]FIG. 18 is a diagram showing the waking mechanism according to the present invention,

[0049]FIG. 19 is a diagram showing a mounting structure of an arm portion, and

[0050]FIG. 20 is a diagram showing the mounting structure of the arm portion.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

[0051] The particulars shown herein are by way of example and for purposes of illustrative discussion of an embodiment of the present invention. The description taken with the drawings makes it apparent to those skilled in the art how the present invention may be embodied in practice.

[0052]FIG. 1 is a perspective view showing an external appearance of a biped toy that can walk on two feet according to the present invention. A toy main body 1 is made to mimic a robot and is constructed by assembling together a head portion 10, a torso 20, two arm portions 30 and two legs 40. A waking action according to the invention is realized by shifting the torso so that the weight of the torso is shifted and shifting the center of gravity of the toy betwee the two legs 40, and actions of the head portion 10 and the two arm portions 30 are not associated with the walking action but in order to realize natural walking actions the head portion and the two arm portions are made to move in association with the actions of the torso and the two legs.

[0053] Next, referring to FIGS. 2 and 3, a mounting structure of the left leg will be described.

[0054] In the present invention, the left and right legs are identical and therefore only the left leg will be described as a matter of conveniences. The left leg 40 is rotatably supported on the torso 20 via a shaft 401 and is constituted by three constituent members such as an upper leg portion 41, a lower leg portion 42 and a foot portion 43.

[0055] In addition, the left leg 40 has four joint portions so that a walking action as natural as that of a human being can be realized.

[0056] Namely, the four joint portions are a hip joint portion 44, a knee joint portion 45, a joint portion 46 for allowing back and forth or longitudinal movements and a joint portion 47 for allowing left and right or lateral movements. The entirety of the left leg is rotatably secured to the torso 20 via the shaft 401 to thereby constitute the hip joint portion 44.

[0057] The upper leg portion 41 is rotatably secured to the lower leg portion 42 via a shaft 402 to thereby constitute the knee joint portion 45, whereby the upper leg portion and the lower leg portion are allowed to swing back and forth, as well as left and right directions.

[0058] In addition, the lower leg portion 43 is rotatably secured to the foot portion 43 via a shaft 403 to thereby the longitudinally moving joint portion 46 and the laterally moving joint portion 47, whereby the foot portion 43 is allowed to tiltably move longitudinally and laterally.

[0059] The mounting structure of the left leg which allows those movements will be described in greater detail with reference to FIG. 3.

[0060] As shown in FIG. 3, five link members are disposed in the interior of the left leg, so that the rotating motion of a motor is converted into reciprocating motion, whereby the toy main body performs walking actions on two feet.

[0061] In other words, disposed on the upper leg portion 41 sequentially from the outside are the first link member 404, the third link member 406 and the fifth link member 408 and a plurality of coupling members 212, 213, 214 are interposed between the link members so as to rotatably couple them together, respectively. In addition, disposed on the lower leg portion 42 sequentially from the outside are the second link member 405 and the fourth link member 407 and a plurality of coupling members 409, 410 are interposed between the link members so as to rotatably couple them together, respectively. Furthermore, the first link member 404 and the second link member 405 are rotatably coupled to each other at an intermediate coupling member 411 via an engagement pin 411 a, and the third link member 406 and the fourth link member 407 are also rotatably coupled to each other at an intermediate coupling member 412 via a coupling pin 412 a.

[0062] Next, referring to FIGS. 4 to 6, a transmission mechanism will be described through which the driving force of the motor is transmitted to those link members.

[0063]FIG. 4 shows a positional relationship between a disc cam and a plurality of levers, FIG. 5 is an enlarged view of FIGS. 4, and 6 is an exploded perspective view showing a positional relationship between the levers and a plurality of link members which are disposed below the levers.

[0064] A member shown at the center of FIG. 4 is installed in the torso 20 and only a transmission mechanism is shown for transmitting power laterally. A power transmission mechanism for the right leg exists on an opposite side of a motor unit 201. The power transmission mechanism for the right leg is constructed the same as the transmission mechanism for the left leg except that a member identical to a circular cam 202 is formed with inner grooves 202 a and outer grooves 202 b which are disposed so as to be shifted 180 degrees relative to inner grooves 202 a and outer grooves 202 b of a circular cam 202 for the left leg. Accommodated in the motor unit 201 are a motor and a series of groups of gears, and the driving force of the motor is transmitted to an output shaft 206 extending to project from an inner frame 205 via the series of groups of gears. The output shaft 206 passes through the disc cam 202 and an outer frame 207. The inner grooves 202 a and the outer grooves 202 b are formed in both sides of the disc cam, and guide pins formed on the four levers are adapted to be guided by the grooves for formed.

[0065] The guide pin 208 a of the first lever 208 is guided in the outer groove 202 b in the external surface (front side) of the disc cam so as to operate the leg 40 in such a manner as to tilt it back and forth. Similarly, the guide pin 209 a of the second lever 209 is guided in the inner groove 202 a in the external surface of the disc cam so as to operate the leg 40 in such a manner as to tilt it left and right. On the other hand, the guide pin 210 a of the third lever 210 is guided in the outer groove (not shown) in the internal surface (opposite side) of the disc cam so as to operate the lower leg portion in such a manner as to swing it left and right. Similarly, the guide pin 211 a of the fourth lever 211 is guided in the inner groove in the internal surface (not shown) so as to operate the upper leg in such a manner as to swing it left and right.

[0066] Bearings 208 b, 210 b are formed at distal ends of the first lever 208 and the third lever 210, respectively, and the bearings are fittingly inserted over a shaft 205 a on an inner frame 205. In addition, bearings 209 b, 211 b are formed at central end portions of the second lever 209 and fourth lever 211, respectively and the bearings are fittingly inserted over a shaft 205 b on the inner frame 205.

[0067] According to the construction, the rotating force of the motor is transmitted to the disc cam 20, and since the guide pins of the four levers are guided in the grooves, respectively, the four lever members are allowed to swing in accordance with the configurations of the respective grooves.

[0068] In addition, notched portions 208 c, 209 c, 210 c, 211 c are formed in lower end portions of the lever members, respectively, and as shown in FIG. 5, a plurality of coupling pins are brought into engagement with the notched portions, respectively.

[0069] Namely, a pin 212 a on the coupling member 212 is brought into engagement with the notched portion 208 c in the first lever, and a pin 213 a on the coupling member 213 is brought into engagement with the notched portion 209 c in the second lever. A pin 214 a on the coupling member 214 is brought into engagement with the notched portion 211 c in the fourth lever, and a pin 41 a on an inner frame 41A of the upper leg is brought into engagement with the notched portion 211 c in the fourth lever. Additionally, the first lever 208 is linked to the third link member 406 through the engagement of the coupling member 212 with the third link member 406 via an engagement pin 212 b. In addition, the third lever 209 is linked to the first link member 404 through the engagement of the coupling member 213 with the first link member 404 via an engagement pin 213 b.

[0070] On the other hand, the third lever 210 is linked to the fifth link member 408 through the engagement of the coupling member 214 with the fifth link member via an engagement pin 214 b.

[0071] As shown in FIG. 6, the first link member 404 and the third link member 406 are disposed on the inner frame 41A and an outer frame 41B of the upper leg portion, and the shaft 401 is allowed to pass through shaft holes 41 b, 213 c, 212 c, 41 b, 214 c sequentially, whereby the upper leg portion 41 can be swung left and right on the shaft 401 as a fulcrum.

[0072] In this positional relationship, the fifth link member 408 is disposed on a rear side of the inner frame 41A. In addition, the second link member 405 and the fourth link member 407 are disposed on an inner frame 41A and an outer frame 41B of the lower leg portion, respectively, and the shaft 402 is allowed to pass through shaft holes 42 a, 412 b, 411 b, 42 a sequentially, while another shaft 403 is allowed to pass through shaft holes 42 b, 410 b, 409 b, 42 b, respectively, so that both the frames are screwed together.

[0073] Next, referring to FIGS. 6 and 7, a mounting structure of the foot portion will be described below.

[0074]FIG. 7 is an enlarged perspective view of a mounting structure of the foot portion. Provided on a surface of the foot portion 43 is a pair of ribs 43 a which is normal to the traveling direction thereof and another rib 43 b between the pair of ribs in such a manner as to protrude from the surface of the foot portion 43, and the second link member 405 and the coupling member 409 are locked to the rib 43 via a shaft 409 a, and the fourth link member 407 and the coupling member 410 are rotatably secured to the foot portion 43 between the pair of ribs 43 a via a shaft 43 c. According to this mounting construction, when the second link member 405 is pulled up, since the center of gravity of the foot portion is positioned inwardly, the foot portion 43 tilts rightward (inwardly) on the shaft 43 c as a fulcrum. Then, when the second link member 405 is pulled down thereafter, the foot portion 43 tilts leftward (outwardly) on the shaft 43 c as the fulcrum. Additionally, when the fourth link member 407 is pulled up, the foot portion 43 is tilted up at the toe on the shaft 403 as a fulcrum, and when the fourth link member is pulled down thereafter, the toe of the foot portion 43 is also tilted down.

[0075] Next, referring to FIGS. 8 to 11, operations of the upper leg portion, the lower portion and the foot portion will be described. In all the figures so referred to, the disc cam rotates counterclockwise. As the disc cam so rotates, the operations of the levers follow the configurations of the associated grooves, respectively. In other words, the guide pins are pushed outwardly in a portion of the grooves where a direct distance between the center of the disc cam to the respective grooves is increased at all times, while the pins are pushed inwardly in a portion of the grooves where the direct distance is decreased at all times. Due to this, the levers are swung clockwise when the guide pins reside in the portion of the grooves where they are pushed outwardly, while the levers are swung counterclockwise when the guide pins reside in the portion of the grooves where they are pushed inwardly.

[0076]FIG. 8 is a diagram showing a state in which the upper leg portion is swung left and right. The guide pin 211 a on the fourth lever 211 is guided in the inner groove (indicated by dotted lines) formed in the back side of the disc cam 202 disposed inside the torso 20. When the driving force of the motor is transmitted to the output shaft 206, the disc cam rotates counterclockwise (in a direction indicated by an arrow), and the fourth lever 211 is swung clockwise (in a direction indicated by an arrow), this swinging the upper leg portion 41 counterclockwise (in a direction indicated by an arrow) on the shaft 401 as a fulcrum. In the figure, reference numeral 402 denotes a fulcrum for the lower leg portion 42.

[0077]FIG. 9 is a diagram showing a state in which the lower leg portion is swung left and right. The guide pin 210 a on the third lever 210 is guided in the outer groove (indicated by dotted lines) formed in the back side of the disc cam 202 disposed inside the torso. When the driving force of the motor is transmitted to the output shaft 206, the disc cam 202 rotates counterclockwise (in a direction indicated by an arrow), and the third lever 210 is swung clockwise (in a direction indicated by an arrow) on the shaft 205 a as a fulcrum. Then, since the coupling member 214 is swung counterclockwise on the shaft 401 as a fulcrum, the fifth link member 408 is pushed down in a direction indicated by an arrow, and as a result, the lower leg portion is swung counterclockwise (in a direction indicated by an arrow) on the shaft 402 as a fulcrum.

[0078]FIG. 10 is a diagram showing a state in which the foot portion is tilted back and forth. The guide pin 208 a on the first lever 208 is guided in the outer groove 202 b formed in the front surface of the disc cam 202 disposed inside the torso 20. When the driving force of the motor is transmitted to the output shaft 206, the disc cam 202 rotates counterclockwise (in a direction indicated by an arrow), and the first lever 208 is swung clockwise (in a direction indicated by an arrow) on the shaft 401 as a fulcrum. Then, since the coupling member 212 is swung counterclockwise (in a direction indicated by an arrow), the third link member 406 is pushed down in a direction indicated by an arrow, and the intermediate coupling member 412 is swung counterclockwise. In addition, since the fourth link member 407 is pushed down in a direction indicated by an arrow, the foot portion 43 is allowed to tilt at the toe in a direction indicated by an arrow on the shaft 403 as a fulcrum.

[0079] Next, FIG. 11 is a diagram showing a state in which the foot portion is tilted left and right. The guide pin 209 a on the second lever 209 is guided in the inner groove 202 a formed in the front surface of the disc cam 202 disposed inside the torso 20. When the driving force of the motor is transmitted to the output shaft 206 of the motor, the disc cam 202 rotates counterclockwise (in a direction indicated by an arrow) and the second lever 209 is swung clockwise (in a direction indicated by an arrow) on the shaft 401 as a fulcrum. Then, since the coupling member 213 is swung counterclockwise on the shaft 401 as a fulcrum, the first link member 404 is pushed down in a direction indicated by an arrow, and the intermediate member 411 is swung counterclockwise. In addition, since the second link member 405 is pushed down in a direction indicated by an arrow, the foot portion 43 is allowed to tilt leftward (outwardly) on the shaft 43 c as a fulcrum.

[0080] Furthermore, a state in which the foot portion is tilted left and right will be described referring to FIGS. 12 to 14. These figures are cross sectional views taken along the line A-A′ of FIG. 7.

[0081]FIG. 12 shows a state in which the second link member 405 is pushed down to a lowest position, and as this occurs the foot portion 43 operates to tilt leftward (outwardly) on the shaft 43 c as the fulcrum. Thereafter, as shown in FIG. 13, when the second link member 405 is lifted up such that the second link member 405 stays horizontal, the foot portion 43 operates to become horizontal on the shaft 43 c as the fulcrum. Then, as shown in FIG. 14, when the second link member 405 is lifted up to a highest position, the foot portion 43 operates to tilt rightward (inwardly) on the shaft 43 c as the fulcrum.

[0082] Next, a walking mechanism will be described referring to FIGS. 15 to 18. In all the figures so referred to, upper diagrams are right side views showing a state in which the toy walks while stretching and flexing the two legs, while lower diagrams are back views showing the inclination of the torso 20 associated with states shown in the upper diagrams, respectively. In the figures, reference character L denotes the left foot and R a right foot. In all the four diagrams, operations to be described therein are those resulting when the disc cam 202 rotates half.

[0083] Firstly, in FIG. 15, the right foot 41R is stepped forward by a step, and the center of gravity is positioned directly above the left foot 41L, in which state the torso is inclined toward the left foot side. In FIG. 16, the torso 20 is inclined from the left foot 41L side to the right foot 41R side with the weight of the torso 20 having been shifted in the state shown in FIG. 15. FIG. 17 shows a state in which the left foot 41L is being stepped forward by a step from the state shown in FIG. 16 after the torso 20 has been so shifted, and in this state, the torso 20 is shifted rearward in order to maintain the balance of the torso 20 as a whole. Then, FIG. 18 shows a state in which the left foot 41L is stepped forward by a step from the state shown in FIG. 17 with the center of gravity being positioned directly above the right foot 41R, in which state the torso 20 is inclined toward the right foot side R. By repeating these actions the toy main body can step forward by a step. Thereafter, in order to move forward the right foot R by a step, the weight of the torso 20 is shifted from the right foot side to the left foot side and the right foot is lifted up while shifting the torso rearward, whereby the right foot is stepped forward by a step. By repeating the series of actions the toy main body can walk on two feet.

[0084] Next, referring to FIGS. 2, 4, 19 and 20, a mounting structure of the arm portions to the torso will be described.

[0085] As shown in FIG. 2, the arm portion 30 is constituted by an upper arm portion 31 and a lower arm portion 32 and is mounted to the torso 20 via a shaft 207 a in such a manner as to move back and forth. Two shafts 207 a and 207 b are provided on an external frame 207 of the torso in such a manner as to protrude therefrom, and after a coupling member 301 is loosely fitted on the shaft 207 a, and an oscillating member 302, a holding member 303 and a pinion 304 are inserted on a bearing 301 a of the coupling member 301. In addition, a bearing 302 b disposed in a lower end portion of the oscillating member 302 is loosely fitted on the shaft 207 b. Then, a rotating body having an eccentric pin 305 a is fitted in a hole 207 c opened in the center of the external frame and an output shaft 206 of a motor is extended. According to the mounting construction, a guide pin 301 b of the coupling member and a guide pin of the rotating body are guided in a longitudinal elongate hole 302 c in the oscillating member 302, whereby when the driving force of the motor is transmitted to the output shaft 26, since the rotating body rotates counterclockwise, the coupling member 301 is oscillated in synchronism with the lateral oscillation of the oscillating member 302. As a result, the upper arm portion 31 mounted to a distal end of the coupling member operates to be oscillated back and forth.

[0086] Next, referring to FIG. 20, an internal structure of the arm portion will be described.

[0087] As shown in the figure, the upper arm portion is constituted by an internal frame 31A and an external frame 31B, and similarly, the lower arm portion is also constituted by an internal frame 32A and an external frame 32B. A shaft 305 a on a pinion 305 extends into a hole 31 a in the internal frame 31A of the upper arm portion, and a rotating body having an eccentric pin 306 a is rotatably secured to the shaft 305 a via hole 306 b. Then, the eccentric pin 306 a is rotatably secured in a hole 307 a in a distal end portion of a link member 307, and a bearing 307 b provided at a rear end portion of the link member is rotatably mounted on a pin 32 a provided so as to erect on the internal frame 32A of the lower arm portion. In addition, a cylindrical shaft 301 a is rotatably secured in a shaft hole 31 b provided so as to protrude on the internal frame 32A of the upper arm portion. The internal frame 31A of the upper arm portion, the internal frame 32A of the lower arm portion, the external frame 32B of the lower arm portion and the external frame 31B of the upper arm portion are assembled sequentially with a pin 308. According to this mounting construction, since the cylindrical shaft 301 a rotates, the upper arm portion 31 operates to be swung back and forth, and when the upper arm rotates, the pinion 305 rotates while meshing with another pinion 304, and therefore the rotating body 306 also rotates in synchronism therewith. The rotating force so generated is then converted into reciprocating motion for transmission to the link member 307, whereby the lower arm portion 32 operates to be swung back and forth on the shaft 308 as a fulcrum.

[0088] Finally, referring to FIGS. 4 and 19, a mounting structure of the head portion and the operation thereof will be described.

[0089] As shown in FIG. 4, the head portion 10 is constituted by a base 101, a rotating body 103, a link member 104 and the like, and a long shaft 101 a is provided so as to erect from the center thereof and a pin 101 b is also provided so as to erect at a position on one side of the base. A crank member 102 is fitted on the pin 101 b via a hole 102 a. In addition, a distal end portion 302 d of the oscillating member shown in FIG. 19 is guided in a notched portion 102 b in the crank member. Then, a rotating member 103 having a cylindrical shaft 103 a is fitted over the long shaft 101 a. A projection 102 c is provided at an opposite end to the notched portion on the crank member in such a manner as to erect therefrom, and similarly, a projection 103 b is provided on an outer circumference of the rotating body in such a manner as erect therefrom. Then, the link member 104 is fitted on the projections, respectively, via holes 104 a, 104 b. After having been fabricated as has been described heretofore, a flat plate 105 is screwed and a head 106 is placed thereon. According to the construction, when the oscillating member 302 oscillates back and forth, since the crank member 102 swings back and forth, the rotating member 103 rotates with a predetermined stroke, whereby the whole head portion operates to rotate in left and right directions.

[0090] Thus, while the embodiment of the present invention has been described heretofore, the present invention is not limited to what has been described. For example, the fulcrum of the foot portion does not have to be positioned inwardly but may be positioned outwardly. In addition, the configurations of the inner and outer grooves in the disc cam may be varied freely, whereby the motion of the two-feet walking can be varied.

[0091] The present invention may be embodied as has been described heretofore, and the following advantages can be provided.

[0092] According to the present invention, the toy main body can walk as naturally as a human being walks by shifting the weight of the toy main body and shifting the center of gravity thereof between the legs without falling down due to the lost of the balance thereof.

[0093] In addition, according to the present invention, the feet can be moved by alternately positioning the center of gravity above one of the left and right legs which supports the toy main body.

[0094] Furthermore, according to the present invention, since unstable actions of the leg portions can be eliminated by positioning the fulcrums of the leg portions rearward, when walking on two feet, the toy main body can keep the balance thereof.

[0095] Moreover, according to the present invention, since the torso can be inclined forward by positioning the fulcrum of the torso rearward, when walking on two feet, the toy main body can keep the balance thereof.

[0096] In addition, since unstable actions of the foot portions can be eliminated by positioning the fulcrums of the foot portions either inwardly or outwardly, the toy main body can keep the balance thereof.

[0097] It is apparent to those skilled in the art that the prevent invention may be modified variously without departing from the sprit and scope of claims of the present invention which will be described below. 

What is claimed is:
 1. A biped toy that can walk on two feet by virtue of the driving force of a motor, wherein legs are rotatably supported on a torso, wherein said motor having disc cams mounted on an output shaft thereof and levers for transmitting the rotations of said cams are disposed in the interior of said torso, wherein said legs are each constituted by leg portions and a foot portion, said leg portions and said foot portion being each rotatably supported, and wherein a link mechanism is disposed in each of said legs to which the driving force is transmitted by said levers, whereby with the right leg of said legs being stepped forward by a step a toy main body is inclined leftward so that the center of gravity thereof is positioned directly above the left leg of said legs, then, in order to allow said left leg to alternately be stepped forward by a step said center of gravity is shifted to said right leg, and after said center of gravity has been so shifted said left leg is lifted up while said torso is being shifted rearward so that the weight thereof is so shifted for advancement.
 2. A biped toy that can walk on two feet as set forth in claim 1, wherein said biped toy can walk while lifting up said left and right legs alternately by positioning said center of gravity above either said left leg or said right leg which bears the weight of said toy main body.
 3. A biped toy that can walk on two feet as set forth in claim 1, wherein joint portions of said leg portions can be flexed in a certain direction by positioning fulcrums of said leg portions rearward.
 4. A biped toy that can walk on two feet as set forth in any of claim 1, wherein said torso can be inclined forward by positioning a fulcrum of said torso rearward.
 5. A biped toy that can walk on two feet as set forth in any of claim 1, wherein the balance of said toy main body can be maintained by positioning fulcrums of said foot portions inwardly or outwardly. 